The period before birth is the final frontier of investigation in human health and development. Interest in fetal origins of childhood and adult well-being has increased exponentially in recent years. We have been documenting normative development of the fetus for the past 16 years under the auspices of this award. Our goals have, and continue to be, threefold. These include: characterizing normal patterns of development of fetal neurobehavioral and physiological functioning during gestation in healthy, low risk pregnancies (Ontogeny); determining how maternal mediators, both psychological and physiological, affect the course of antenatal development (Maternal Influences), and evaluating within and cross-domain continuity in function from prenatal to postnatal development within individuals as a means of understanding the origins of individual differences (Prediction). This project period will focus on further defining the effects of evoked fetal reactivity on maternal function, and evoked maternal reactivity on fetal functioning. This endeavor was generated by findings in the current project period that revealed temporal, bidirectional linkages within the maternal-fetal pair. Two prenatal studies are proposed. The first (n = 52) examines the capacity of an evoked fetal response generated by auditory stimulus presentation to elicit a maternal physiological response at three gestational periods (24, 30, and 36 weeks). The second (n = 108) evaluates fetal responsivity to maternal arousal evoked within a pregnancy specific context at four gestational periods (18, 24, 30, and 36 weeks). Both studies include indicators of maternal autonomic (heart rate, vagal tone, skin conductance, respiration) and neurohormonal (salivary cortisol) activation; fetal measures focus on heart rate and its patterning, motor activity, and the relation between the two. Pairs will be followed at 5 months postnatal age to determine how features of prenatal maternal-fetal synchrony and responsiveness to one another contribute to the unfolding maternal-infant relationship, as measured by the degree of behavioral and physiological synchrony during an undisturbed, baseline interactive period and a still-face condition designed to disrupt the temporal regulatory process between the pair. This project will further our understanding of the maternal factors that impinge, positively or negatively, on the developing fetus and the origins of the earliest relationship. PUBLIC HEALTH RELEVANCE: There is tremendous recent interest in characterizing how development proceeds before birth and its implications for later life. In this study we will investigate how maternal physiology and emotions affect the development of the fetus and how the developing fetus may affect the pregnant woman. We will apply this information to understanding how mothers interact with their infants during their first year of life.